153 replies to this topic

[turbobob]

As my other thread seemed to go a bit off topic, i.e. MMG stage 2 dyno turned into a thread of Intercooler vs Chargecooler, I thought I'd start another thread deidicated to Intercooler vs chargecoolers. Whilst looking into this topic I came across this article : How can an air-to-air intercooler be more efficient than a water based intercooler? There is an overwhelming quantity of ambient air available to cool an air-to-air core relative to the charge air thru the inside of the intercooler. At just 60 mph, with a 300 bhp engine at full throttle, the ambient air available to cool the intercooler is about ten times the amount of charge air needed to make the 300 hp. Whereas the water intercooler largely stores the heat in the water until off throttle allows a reverse exchange. Some heat is expelled from a front mounted pre-rad, but the temperature difference between the water and ambient air is not large enough to drive out much heat. Another way to view the situation is that ultimately the heat removed from the air charge must go into the atmosphere regardless of whether it's from an air intercooler or a water based intercooler. The problem with the water intercooler is that the heat has more barriers to cross to reach the atmosphere than the air intercooler. Like it or not, each barrier represents a resistance to the transfer of heat. The net result; more barriers, less heat transfer. Street use: The air-to-air intercooler will prove superior in efficiency. Drag racing: Charge cooler,The short spurt of power allows the iced water to cool the charge air to below ambient temperature. Track and racing: The air-to-air intercooler is clearly superior due to the shorter route of getting the heat out of the air charge and into the atmosphere. CHARGE COOLERS:- A charge-cooler (CC) is a device where the ambient air cools water, which in turn cools the intake air. In essence a charge-cooler consisting of two "radiators". WHAT'S SO GOOD ABOUT THEM? The "plumbing" is the deciding factor. It is sometimes impossible to get big (50-75mm) air ducts from the engine to the front of the engine bay, but a flexible water pipe can be fitted easily. Another advantage of a charge-cooler is it thermal mass, which is very high due to the water. This means that the intake air will not change drastically when the car stops moving. WHAT'S SO BAD ABOUT THEM? Charge-coolers are less efficient and more costly than inter-coolers, because the heat has to travel over more transfer surfaces. An inter-cooler transfer is: ambient air/metal/intake air, where a charge-cooler is: ambient air/metal/water/metal/intake air. It is a thermodynamics law, which states that heat (energy) can flow only when there is a temperature difference. Chargecoolers only have a finite amount of cooling water, if you can't cool that water you start to build up heat. For example, hard track use will almost certainly heat up a chargecooler enough to stop it working effectively. Take into account the weight of a pre-rad, pump, reservoir and a couple of litres of water and it makes even less sense. ETA sorry about the shite spelling on my behalf on the thread topic. Trouble is you can't edit the thread topic

Edited by turbobob, 21 June 2010 - 07:33 PM.

[siztenboots]

water is 4.2 times better for heat transfer , its also much easier to package the system

[techieboy]

Couldn't care less, either way. But I'm betting that article is written with FMIC's and not mid-mounted engines (with a not exactly massive air scoop on the side of the car) in mind. I'd imagine that seriously alters the advantage vs disadvantage equation.

[Zoobeef]

water is 4.2 times better for heat transfer , its also much easier to package the system

Thats why the main tuners in england and europe offer a cc over a larger intercooler

[JohnTurbo]

I'm a mechanical engineer. Masters degree no less. Water is an excellent conductor of heat. - That said an intercooler has air-ally and ally to air interfaces. CC has air to ally, ally to water, water to ally, ally to air. We all go air air in the end, and so steady state the chargecooler will be less efficient for any given tranfer area/design. CC only suits the VX better because we cannot have a FMIC, and nowhere is suitable for a large IC at the rear. I'd be interested in some kind of heatpipe design for cooling charge air. Google it.

[turbobob]

Like I said in my other thread, the only time you have an issue with insufficient air flow is when the car is stationary, and you aren't ragging the car when you aren't moving. So it isn't an issue. And besides if it was an issue, the standard intercooler wouldn't be adequate either. Charge coolers essentially have the same effect as an intercooler, but more inffeicient. You transfer the heat into water, then move that heat somewhere else, to be transfered back into air again, i.e. in essence of what an intercooler does, but with more stages. However water is limited to 100 degrees C before you reach saturation. And you have several heat transfer cycles, making it far more inefficient than an intercooler. Maybe TMS and CS offer intercoolers. But correct me if I'm wrong, but aren't most / all Dakar rally cars fitted with intercoolers? And I may be being cynical here, but fitting a charge cooler is far more labour intensive than fitting an intercooler, hence more profitable to fit a chargecooler.

[turbobob]

water is 4.2 times better for heat transfer , its also much easier to package the system

How can it be easier to package the system when an intercooler is essentially one component and a charge coolers are several components?

[markiii]

water is 4.2 times better for heat transfer , its also much easier to package the system

How can it be easier to package the system when an intercooler is essentially one component and a charge coolers are several components?

because the heat exchanger core can't be placed in decent airflow due to the VX being midengined

Edited by markiii, 21 June 2010 - 09:06 PM.

[JohnTurbo]

This thread is funny. Can we all agree that the best place for airflow is the front of the car, and that we can't put an intercooler there. Maybe with ducting an ic can be made to work well near the engine. This is the only thing to discuss. Can an ic be placed so that it is as good as a chargecooler? Id like to propose a third option however. Stock ic plus Devils own alcohol injection.

[markiii]

think exige scoop and maybe

[jaylin]

Surely CS or Pro Alloy must have done some testing before going with the CC? Personally I can't see an intercooler cooling enough/as well on a 300bhp mid engine car with poor air flow...

Edited by jaylin, 21 June 2010 - 09:49 PM.

[slindborg]

lol that article is some posts that were complied into sense and published as a word doc. I have a copy of that on my site www.slindborg.host.sk or http://slindborg.hostei.com/

Edited by slindborg, 21 June 2010 - 09:45 PM.

[P11 COV]

A snorkal Chris Randalls Europa is around the 400bhp mark for the GT championship. Not chargecooled though I think?

Edited by P11 COV, 21 June 2010 - 09:55 PM.

[jaylin]

lol that article is some posts that were complied into sense and published as a word doc. I have a copy of that on my site

www.slindborg.host.sk or http://slindborg.hostei.com/

Good article slindborg, read 90% of it while slurping my vino.

Confirms my thoughts...

[Crabash]

A snorkal Chris Randalls Europa is around the 400bhp mark for the GT championship. Not chargecooled though I think?

It is C/C and the snorkel is to feed extra air to the intake, he was playing around trying to make a bespoke airbox.

Edited by Crabash, 21 June 2010 - 10:10 PM.

[MrSimba]

Red Bull Exige

[techieboy]

Yep, no packaging problems at all there.

[slindborg]

heat soak on the grid-tastic CC is ace, but packaging and cost is high compared to simply lobbing an air to air AFTERcooler in. I wonder how effective a system might be if you had a mocal oil cooler style rad in an ear running water for the CC.

[siztenboots]

Red Bull Exige

see , I/C easily packaged, must be really fast in reverse gear

Edited by siztenboots, 22 June 2010 - 08:20 AM.

[Exmantaa]

Red Bull Exige

Saw that before, but not so sure on this solution for a supercharged engine.
The IC with ducting is all adding volume after the TB...